For the orthodontic treatment of patients there are inter alia the following two alternatives:
In a first alternative having fixed braces brackets are glued onto the teeth of the patient which are to be treated and connected to one another by an orthodontic wire. The brackets have a pad for connection to the tooth and a bracketbody having a slot which receives the archwire. The brackets can be arranged buccally or lingually.
In a second alternative, small guidance elements are glued onto the teeth of the patient which are to be treated. The patient receives a corresponding treatment splint into which the patient “bites”, whereby the guidance elements on the teeth engage with correspondingly assigned guiding pockets in the treatment splint. The guiding pockets are arranged in the treatment splint such that they exert the desired orthodontic forces and/or torques onto the teeth via the guidance elements.
Generally, in this alternative the complete orthodontic treatment of the patient is planned at the computer by means of a software, i.e. an existing initial situation is converted into a desired target situation: for that purpose the guidance elements, for example from a predefined library of guidance elements, are arranged on the teeth which are to be treated. Subsequently, different treatment stages are defined within which certain partial steps of the treatment shall be achieved. For each of these treatment stages a treatment splint is calculated and produced subsequently. If treatments are necessary in the upper and in the lower jaw, the patient receives the necessary treatment splints for the upper and for the lower jaw for each treatment step. After completion of a treatment stage the patient exchanges the treatment splint, i.e. he exchanges the “old” for the “new” treatment splint, until the treatment is completed. Usually, in this treatment which is also called aligner therapy as a rule 20 treatment stages are defined, wherein a lower or higher number of stages is possible, too, though.
It is a disadvantage of the first alternative that with buccal brackets it is optically not attractive and also involves a high hygienic effort on the side of the patient.
A disadvantage of the second alternative is that certain treatment steps, for example the rotation or angulation or extrusion of a tooth, can be carried out only difficulty or not at all with the treatment splints.